Impervious fabric



Patented May 26, 1936 UNITED STATES PATENT OFFICE IMPERVIOUS FABRICJames K. Hunt, Wilmington, Del., assignor to E. L du Pont de Nemours &Company, Wilmington, Del., a corporation of Delaware No Drawing.Application August 1,. 1933, Serial No. 683,159

5 Claims.

viously must be substantially insoluble in gasoline and other liquidfuels which may pass through the fuel pump. At low operatingtemperatures, such coated fabric diaphragms tend to lose flexibility,particularly on aging, resulting in impaired efficiency of the fuelpump, that is, the quantity of liquid fuel which the pump was originally capable of handling is materially lessened. A similar loss offlexibility exists in the case of oil impregnated clothing such asslickers, gloves, hats, and the like. I

An object of the present invention is the preparation of such a fabrichaving improved flexibility at low temperatures. A still further objectis the preparation of such fabric with improved flexibilityretention, afurther object is the prepara tion of improved oil pump diaphragms,clothing, and the like. Other objects-will appear hereinafter.

' These objects are accomplished by the following invention wherein the.fabric is impregnated with an oil composition containing a materialthreads per inch in each direction, having'preferably less than 1% ofstarch and1% of moisture, and free from traces of acid, is fed throughrollers into a tank containing the material for the first or base coatand then passed through a-drying oven. Two coats are applied to eachside of the cloth and drying is carried out between each successivecoating. Various types of oils may be used, for example linseed oil,China-wood oil,,sun-.

flower seed oil, rubber seed oil, soya bean oil,

"perilla oil, citioica oil, menhaden (fish) oil, etc.,

or suitable mixtures of such oils. The oil or mix- .ture of oils ascommonly used is generally given 'a preliminary bodying treatmentinvolving blowing with air at a temperature of approximately 212 F. orheat treating in the substantial absence of air at a more elevatedtemperature, for example 500-600" F. The resulting bodied oil is usuallythinned with raw oil, (linseed, China wood, sunflower seed, etc.) orwith a thinner such as mineral spirits, turpentine, or solvent 5naphtha, before being used for impregnating the fabric. The-oil or oilsmay be used either with or a without driers, but driers are commonlyused. The diphenylguanidine or other .agent used is preferablyincorporated with the hot oil but, dissolved in a suitable solvent suchas butyl alcohol,

- may be added to the cold oil. The amount of agent used is of the orderof 0.25% to 2.0%, based on the oil. In general, 0.5% affords optimumresults'. In impregnating the fabric with the oil, the fabric ispreferably passed between the rolls beneath the surface of the oil, theexcess oil being squeezed out by passing the fabric between another pairof rolls above the surface of the oil. For the first coat thinned oil isgenerally used, but 20 for the second and third coats the oil ispreferably used unthinned since the dried first coat is less The firstcoat is usually dried for 4 to 5 hours, the 30' second coat, 5 to '7hours, and the third coat for 8 to 10 hours, each at around F. Ingeneral, the drying is carried no further than is necessary to secure anoil film of suitable physical characteristics including relatively highinsolubility in gasoline or other liquid fuel, since prolonging dryingleads to inflexibility of the oil film in or on the coated fabric. Forfabrics of the type commonly used for fuel pump diaphragms,

the three coatings of oil increase the weight of 40' such articles, asuitable fabric isimpregnated 50 with a drying oil such as linseed oilin much the same'way as the pump diaphragms above disclosed. The use ofthe treated oil of the present invention in the manufacture of theseslickers,

etc., leadsto a superior flexibility on aging, this 55 flexibility beingparticularly noticeable at low temperatures.

Examples illustrating oils suitable for these purposes, and particularlyfor the preparation of oil pump diaphraa'lns are shown below. 60

Example 1 Parts by weight Linseed oil 60.0 China-wood oil 40.0Diphenylguanidine 0.5 Lead-manganese liquid drier 0.5

Concentration such as to give about 0.025% lead and 0.007% manganeseeach as metal on the basis of total oil.

Forty parts of the linseed oil are heated with 40 parts of theChina-wood oil to about 580 F. and held for short string (about 15-20minutes). The remaining 20 parts of linseed oil are then added andheating discontinued. The body of the oil (and therefore the cookingschedule) may vary within rather wide limits depending upon theparticular application of a given oil, but for impregnating the cottonfabric diaphragms of fuel oil pumps, an oil having a viscosity of around36 to '42 poises at 77 F., (before reducing with a thinner as indicatedbelow) has been found to .be quite suitable. The diphenylguanidine maybe added directly to the oil on the down heat, preferably at temperaturebelow the decomposition point (about 338 F.) of diphenylguanidine. Whenother agents are used, the agent should be added when the oil is at atemperature below the decomposition temperature of the particular agentused. The agent may also be added in solution in a suitable solvent, forexample in alcohol in the case of diphenylguanidina after the oil hascooled. The liquid drier should be added on the down heat, preferablyafter the oil is substantially at room temperature. V

For the first coat the oil composition is thinne with the desiredamount, usually 10-30%, of a suitable thinner such as mineral spirits,raw China-wood oil, raw perilla oil, raw rubber seed oil, raw soya beanoil, raw sunflower seed oil, etc. For the second and third coats the oilmay be used without thinning. Instead of diphenylguanidine, asubstantially equal amount of other dior trisubstituted guanidines maybe used, for example, di-o-tolylguanidine, di-xylyl-guanidine,di-naphthylguanidine, tri-phenylguanidine, etc., or a-substantiallyequal amount of catechol, creosole, alpha-naphthol, phenylnaphthylamine,or p-hydroxydiphenyl.

Fuel pump diaphragms impregnated with a treated oil such as that ofExample 1 are not only highly flexible initially, but also exhibit adefinitely higher degree of flexibility on aging than do diaphragmscoated with a similar oil mixture but without diphenylguanidine orsimilar agent. Such superior retention of flexibility is particularlynoted when the pump operating with such a diaphragm is being operated atlower temperatures, minus 20 F. or lower.

Lead-Cobalt liquid drier 0.5

Concentration such as to give about 0.025% lead and 0.005% cobalt, eachas metal on the basis of the total oil.

The oil is treated as in Example 1. The coating operation is carried outas in Example 1.

Lead-manganese-cobalt liquid drier *Concentration such as to give about0.025% lead, 0.005% manganese, and 0.002% cobalt, each as metal on thebasis of the total oil.

Erample 4 Parts by weight China-wood oil 50.0 Linseed oil 50.0Di-o-tolylguanidine 0.5

Example 3 Parts by weight 5 China-wood oil 30.0 Linseed oil 50.0 Soyabean oil 20.0 p-Hydroxydiphenyl 0.75 10 Lead-manganese liquid drier; 0.5

"Concentration such as. to give about 0.025% lead and 0.007% manganese,each as metal on the basis of total oil.

The heating 'of the oil and the coating of the fabric are carried outasin Example 1.{

As many apparently widely diiferenti embodiments of this invention maybe made without departing from the spirit and scope thereof, it is to beunderstood that I do not limit myself to the specific embodimentsthereof except as defined 40 in the appended claims. 5

. I claim: 5

1. An oil pump diaphragm of improved flexibility retention, comprising afabric impregnated with a drying oil containing from 0.25 to 2.0% of 45an agent from the class consisting of; polyaryl guanidines,phenyl-a-naphthylamine, p-ihydruxydiphenyl, catechol, a-naphthol, andcreosole, and

'of'diphenylguanidine, and then dried. f

4. An oil pump diaphragm of improved flexibility retention, comprising afabric impregnated with a drying oil containing from 0.25% to 2.0% ofphenyl-a-naphthylamine, and then dried.

5. An oil pump diaphragm of improved flexibility retention, comprising afabric impregnated with a drying oil containing from 0.25% to 2.0% ofcatechol, and then dried.

JAMES K. HUNT.

